Study: Climate Map Predicting Future African Malaria Outbreaks

Guest essay by Eric Worrall

Scientists have created a RCP8.5 based hydrological model of changes they expect to the distribution of Malaria in Africa. But they admit their model cannot account for artificial changes like dams and irrigation networks.

Malaria: new map shows which areas will be at risk because of global warming

August 29, 2020 12.49am AEST

Mark Smith
Associate Professor in Water Research, University of Leeds

Chris Thomas
Global Professor in Water & Planetary Health, University of Lincoln

Of an estimated 228 million cases of malaria worldwide each year, around 93% are in Africa. This proportion is more or less the same for the 405,000 malaria deaths globally.

That’s why there are huge efforts underway to provide detailed maps of current malaria cases in Africa, and to predict which areas will become more susceptible in future, since such maps are vital to control and treat transmission. Mosquito populations can respond quickly to climate change, so it is also important to understand what global warming means for malaria risk across the continent. 

We have just published a new set of maps in Nature Communications giving the most accurate picture yet of where in Africa will – and won’t – become climatically suitable for malaria transmission.

The malaria parasite thrives where it is warm and wet. Air temperature controls several parts of the transmission cycle, including the mosquito lifespan and rates of development and biting. 

If it is too warm or too cold then either the malaria parasite or the mosquito that transmits the parasite between humans will not survive. This suitable temperature range is relatively well established by field and laboratory studies and forms the basis for current projections of the impact of climate change on malaria.

Read more: https://theconversation.com/malaria-new-map-shows-which-areas-will-be-at-risk-because-of-global-warming-144783

The abstract of the study;

Incorporating hydrology into climate suitability models changes projections of malaria transmission in Africa

M. W. SmithT. WillisL. AlfieriW. H. M. JamesM. A. TriggD. YamazakiA. J. HardyB. BisselinkA. De RooM. G. Macklin & C. J. Thomas 

Abstract

Continental-scale models of malaria climate suitability typically couple well-established temperature-response models with basic estimates of vector habitat availability using rainfall as a proxy. Here we show that across continental Africa, the estimated geographic range of climatic suitability for malaria transmission is more sensitive to the precipitation threshold than the thermal response curve applied. To address this problem we use downscaled daily climate predictions from seven GCMs to run a continental-scale hydrological model for a process-based representation of mosquito breeding habitat availability. A more complex pattern of malaria suitability emerges as water is routed through drainage networks and river corridors serve as year-round transmission foci. The estimated hydro-climatically suitable area for stable malaria transmission is smaller than previous models suggest and shows only a very small increase in state-of-the-art future climate scenarios. However, bigger geographical shifts are observed than with most rainfall threshold models and the pattern of that shift is very different when using a hydrological model to estimate surface water availability for vector breeding.

Read more: https://www.nature.com/articles/s41467-020-18239-5

To their credit the scientists noted that Malaria can thrive in a wide range of temperatures, so this isn’t just another warming = malaria study.

My main concern is I don’t think the study is useful as guide to policy, I doubt it is applicable to the real world. The study is based on RCP8.5, which is vanishingly unlikely to occur, and the study uses fine grained model hydrological projections.

Given climate models disagree wildly with each other and with observations about the extent of global cloud cover, it is difficult to see how you can infer anything useful from current climate model projections of future rainfall patterns.

Below is a diagram from Pat Frank’s paper, Propagation of Error and the Reliability of Global Air Temperature Projections, showing how wildly wrong climate models are about global cloud cover, when projections are compared to observations. Not only are models wrong, they don’t even agree with each other. Not a good basis for reliable hydrological projections, or any kind of projection for that matter.

Page 6, Propagation of Error and the Reliability of Global Air Temperature Projections by Pat Frank

32 thoughts on “Study: Climate Map Predicting Future African Malaria Outbreaks

    • Have to buy Tonic water by the gallon, and a lot of gin to go with it. To numb the pain of all the nonsense going on with everything.

    • Well, I’m prepared. I have my HCQ prescription waiting on the shelf in case I come down with any China virus uh, malaria, symptoms.

    • oh yeah today i heard radio some fool saying taking HQ would be a huge risk of malaria becoming resistant to it
      it already HAS FFS!
      and a few k people taking a 5 day course in NON malarial nation isnt going to make a jot o difference.
      just another stupid git trying a CYA excuse

  1. “Scientists have created a RCP8.5 based hydrological model“

    I’d prefer to call them “researchers”. It is more befitting of the exploratory/provisional nature of what they do and claim. Forget their grand-sounding titles of “professor” etc, a title doesn’t make it science, and doesn’t necessarily qualify them as “scientists”.

    The MSM calls them “scientists” to convey a sense of deep knowledge behind the worry mongering. All the while, most of these people are guessing and speculating. The use of RCP8.5 gets the answer they need to make it newsworthy for the worry monger-MSM symbiosis.

    • “Jordan September 5, 2020 at 12:57 am
      “These people are guessing and speculating”

      This is the honest and ugly truth.
      We have gone through so many comical cycles of these things but amazingly, their credibility is still intact and their fear based anti fossil fuel activism still works.

  2. Malaria does not correlate with temperature. It is controlled by human invention and intervention.

    It was eliminated from Italy (the name originated here: malaria=bad air, the supposed cause of the sickness long ago) by sending out squads of workers to drain the swamps and poison the mosquitoes. Not by changing the weather.

    Malaria was a scourge as far north as Archangel in Russia, which has a slightly lower temperature curve than most parts of Africa.

    If we really want to help Africans save themselves from this terrible bug we might start by letting them use the same tools we used to get rid of it. DDT anyone?

    Rachel Carson’s legacy should be ranked right up there with Hitler’s, Mao’s and Pol Pot’s.

    • Right on, John, Nuke it with DDT and have the people take HCQ. Rachel Carson is a hero of the left, not so much with rational people.

    • griff will be along shortly to remind you that DDT isn’t banned (griff will conveniently forget the millions who died while it was banned). Now it’s permitted at levels that are not always effective.

    • John you nailed it:
      “Malaria does not correlate with temperature. It is controlled by human invention and intervention.”

      The authors of this study seem unaware of even a basic history of Africa since 1500. They have not identified where and why malaria declined significantly in certain areas. They have not asked why malaria then subsequently increased. Could it be certain competent people managed the problem in certain countries for a number of years? Did they even bother to contact people who have grappled with malaria control in African countries over the past fifty years? These are basic questions for any credible study.

  3. The solution is simple if, and that’s a big if, malaria is an issue use more DDT. Banning DDT was a criminal act that caused the deaths of millions, that is the law of unintended consequences the greens as always did not consider the implications of what they were doing.

  4. Reference: https://www.sciencedirect.com/science/article/abs/pii/S0140673612600348

    This Science Direct paper shows that from 1980 to 2004, prior to the Bill and Melinda Gates Foundation (BMGF) malaria control program, malaria death rates in Africa went from 10.3 per thousand population to 18 per thousand population. After the BMGF malaria control program, malaria death rates in Africa declined from 18 per thousand population in 2004 to 1.3 per thousand population in 2010. Globally, both cases and deaths per thousand population have been on a downward trend since 1990.

    In any case, whether or not climate change is a factor, these data show that malaria control programs such as the BMGF program are probably a better response than cutting fossil fuel emissions.

    • Eliminating preventable deaths in the 3rd world is not part of the environmental program, it’s specifically against the program

      • Because Africa is already a collection of socialist hellholes. Those lives are no longer needed. Black lives matter, only to the extent that they are likely to vote in socialism in the US.

  5. At some point there is going to need to be the equivalent of the Nuremberg trials for all of these people and their crimes against humanity.
    I think the trials should occur in Africa and if guilty all scientist/activists should be sentenced to subsistence farming in a malaria area that we create and enclose specifically for them.

    I think Tommy Wils was correct but “will be a lot worse than he thought”.

  6. Model mania. Junk models with untested assumptions run against unrealistic scenarios piled on top of more junk models. Output is just a huge pile of crap.

  7. A major reason for the elimination of malaria in Europe was housing animals separate from humans. Having your goats and cows in an under-croft to take advantage of the warmth they provide in winter was important fot the year to year survival of the mosquitoes.

    I grew up with DDT sprayed onto the indoor walls every year in a hot climate. Treating malaria not only reduces deaths: it reduces morbidity so that people have the energy to work. The more subtle problems are things like being able to safely improve the iron status of pregnant women and young children because higher haemoglobin allows the parasite to start reproducing causing acute illness. Having healthy children reduces birth rates more or less immediately – as soon as the Lippies Loop IUD became available, young women wanting to delay a second baby started coming to Mum’s clinic.

  8. There are valid concerns about malaria — it is deadly. It is not caused by AGW, not even contributed to by AGW. It spreads where local governments are unable to mount effective malaria control efforts. It affects areas in which the population is too poor and social development too low for houses to have windows, window screens or even effective bed nets.

    Malaria is not caused by mosquitoes. It is transmitted from humans with malaria to other humans.

    Most of the Eastern Seaboard of the United States used to be malaria area. It is still suitable for malaria and the mosquito that would transmit malaria (if there were any to be transmitted) is still endemic in most of that area. We fought back the mosquitoes and isolated malaria patients. Now we don’t have endemic malaria.

    Malaria in Africa is a Development Issue — not a weather or climate issue.

    • Two of Stockholm’s most exclusive suburbs Lidingö and Ekerö were shunned 200 years ago because of malaria.

    • Joe
      Thanks for link. It shows how malaria is a disease of poverty, not climate.
      But the header attached to the map says 1 million cases during the
      Civil War, not deaths.

  9. There are NO places in Africa too cold for malaria except the tops of Mt Kenya, Kilimanjaro and Ruwenzori and possibly the highest peaks of the Atlas mountains and the Ethiopian highlands.

    In the first half of the nineteenth centuy the northern limit of malaria in Scandinavia was in areas where the annual average is a couple of degrees above zero (Celsius), the warmest month about 15 C and the coldest about
    -8 C. Try to find somewhere in Africa to match that.

    And the worst malaria epidemic on record was in (wait for it)… Siberia.

  10. Where there is decent housing malaria disappears. Failing this DDT can be used, but it is not a preferred solution.

    For one thing mosquitos don’t develop resistance to houses.

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